Johnson Thomas F, Conti Mariachiara, Iacoviello Francesco, Shearing Paul R, Pullen James, Dimartino Simone, Bracewell Daniel G
Department of Biochemical Engineering, University College London, Bernard Katz, London, WC1E 6BT, UK.
Institute for Bioengineering, School of Engineering, University of Edinburgh, Edinburgh, EH9 3JL, UK.
Anal Bioanal Chem. 2023 Oct;415(24):5961-5971. doi: 10.1007/s00216-023-04866-6. Epub 2023 Jul 31.
X-ray computed tomography was applied in imaging 3D-printed gyroids used for bioseparation in order to visualize and characterize structures from the entire geometry down to individual nanopores. Methacrylate prints were fabricated with feature sizes of 500 µm, 300 µm, and 200 µm, with the material phase exhibiting a porous substructure in all cases. Two X-ray scanners achieved pixel sizes from 5 µm to 16 nm to produce digital representations of samples across multiple length scales as the basis for geometric analysis and flow simulation. At the gyroid scale, imaged samples were visually compared to the original computed-aided designs to analyze printing fidelity across all feature sizes. An individual 500 µm feature, part of the overall gyroid structure, was compared and overlaid between design and imaged volumes, identifying individual printed layers. Internal subvolumes of all feature sizes were segmented into material and void phases for permeable flow analysis. Small pieces of 3D-printed material were optimized for nanotomographic imaging at a pixel size of 63 nm, with all three gyroid samples exhibiting similar geometric characteristics when measured. An average porosity of 45% was obtained that was within the expected design range, and a tortuosity factor of 2.52 was measured. Applying a voidage network map enabled the size, location, and connectivity of pores to be identified, obtaining an average pore size of 793 nm. Using Avizo XLAB at a bulk diffusivity of 7.00 × 10 ms resulted in a simulated material diffusivity of 2.17 × 10 ms ± 0.16 × 10 ms.
X射线计算机断层扫描技术被应用于对用于生物分离的3D打印螺旋面进行成像，以便从整个几何结构到单个纳米孔对结构进行可视化和表征。制作了特征尺寸为500微米、300微米和200微米的甲基丙烯酸酯打印件，在所有情况下材料相均呈现出多孔亚结构。两台X射线扫描仪实现了从5微米到16纳米的像素尺寸，以生成跨多个长度尺度的样品数字表示，作为几何分析和流动模拟的基础。在螺旋面尺度上，将成像后的样品与原始计算机辅助设计进行视觉比较，以分析所有特征尺寸下的打印保真度。将整体螺旋面结构的一个500微米特征单独进行比较，并在设计体积和成像体积之间进行叠加，以识别单个打印层。对所有特征尺寸的内部子体积进行材料相和空隙相分割，以进行渗流分析。对3D打印材料的小块进行了优化，以便在像素尺寸为63纳米的情况下进行纳米断层成像，测量时所有三个螺旋面样品均表现出相似的几何特征。获得的平均孔隙率为45%，在预期设计范围内，测量的曲折因子为2.52。应用空隙网络地图能够识别孔隙的大小、位置和连通性，得到的平均孔径为793纳米。在体扩散率为(7.00×10^{-10} m^2/s)的情况下使用Avizo XLAB，模拟得到的材料扩散率为(2.17×10^{-10} m^2/s ± 0.16×10^{-10} m^2/s)。
